The object of this study is to evaluate eyelid muscle forces and eyelid movement dynamics for their value in diagnosing disorders of eyelid movement and in guiding ptosis surgery. Stiffness and active levator muscle force will be measured by force transducers mounted on a forceps. Eyelid movement will be measured by an ultrasonic (sonar) technique. These studies will be done in normal humans at various ages, and in patients with ptosis, myasthenia, ophthalmoplegias, and abnormalities of lid closure. In adult volunteers and in some patients, electromyography of the levator and orbicularis muscles will be correlated with the above tests.